Mining hasn't changed much in hundreds of years. In most cases, big holes are still dug in the ground using vast amounts of fossil fuels. Ore processing uses massive amounts of power. Large volumes of water are needed. Chemicals like cyanide are used. In many cases, waste is left. And closed mines sometimes leak acid.

But a new set of cleaner technologies are starting to emerge. Innovations from cleantech industries are starting to enter the mining sector. Slowly, mining is cleaning up and becoming more efficient.